Active transport, ion movements, and pH changes

1988 ◽  
Vol 19 (3) ◽  
pp. 225-236
Author(s):  
Norman E. Good
Keyword(s):  
Active Transport ◽  
Ph Changes ◽  
Ion Movements

Active transport, ion movements, and pH changes

1988 ◽  
Vol 19 (3) ◽  
pp. 237-250
Author(s):  
Roger P. Hangarter ◽  
Norman E. Good
Keyword(s):  
Active Transport ◽  
Ph Changes ◽  
Ion Movements

THE EFFECTS OF NEW DIURETICS ON NET ION MOVEMENTS IN SODIUM-RICH SMOOTH MUSCLES

1967 ◽  
Vol 45 (1) ◽  
pp. 149-159 ◽  
Author(s):  
E. E. Daniel
Keyword(s):  
Active Transport ◽  
Ethacrynic Acid ◽  
Smooth Muscles ◽  
Convincing Evidence ◽  
Small Concentration ◽  
K Uptake ◽  
Aldosterone Antagonist ◽  
Ion Movements ◽  
Sufficient Concentration

The effects of furosemide, ethacrynic acid, triamterene, and an aldosterone antagonist (Su-11927) were studied on recovery of electrolyte gradients by Na-rich pieces from rabbit uteri and aortas. In sufficient concentration furosemide and ethacrynic acid appeared to inhibit Na extrusion. Only furosemide inhibited K uptake as well. A small concentration of ethacrynic acid (0.1 μg/ml) increased Na extrusion from Na-rich uterine pieces but did not increase K uptake. Thus K gain and Na extrusion were not always reciprocally related. Triamterene and Su-11927 altered recovery of electrolyte gradients, but convincing evidence for inhibition of Na active transport was not obtained. Whether inhibition of Na extrusion without inhibition of K uptake, as by ethacrynic acid, could be considered convincing evidence of inhibition of active transport was discussed.

scholarly journals Cat Heart Muscle In Vitro

1964 ◽  
Vol 47 (3) ◽  
pp. 531-543 ◽  
Author(s):  
Ernest Page ◽  
R. J. Goerke ◽  
S. R. Storm
Keyword(s):  
Active Transport ◽  
Sucrose Solution ◽  
Ion Movements ◽  
K Concentration ◽  
Ouabain Inhibition ◽  
External Face ◽  
Cat Heart ◽  
Water Contents ◽  
Physiological Value

Cellular concentrations, [K]i, [Na]i, and [Cl]i, and cell water contents were measured in vitro at 27°C in cat papillary muscles. Measurements were made with and without ouabain at varying concentrations of K and ouabain, at pH 5.2 and 9.0, in absence of O2, and in NaCl-free solution. Large losses of cell K and increases of cell Na occurred in presence of ouabain, at 2–3°C, and in K-free medium. The dependence of inhibition of cation transport by ouabain on external K concentration, studied at constant initial [K]i, was consistent with a competition between K and ouabain localized to the external face of the membrane. In NaCl-free sucrose solution [K]i remained at its physiological value and was not affected by exposure to ouabain or low temperature, except when Ca was also omitted. Ouabain inhibition persisted at pH 9.0 and in Ca-poor media. Cells swelled and lost K at pH 5.2, and residual ouabain effect was small. At pH 9.0, or in absence of O2, or in Ca-poor solutions cells became permeable to mannitol. The ion movements observed after inhibition of active transport are compatible either with a passive K distribution and a primary inhibition of Na extrusion or with inhibition of a coupled active transport of both K and Na.

On the structural organization of biological pumps and channels

1984 ◽  
Vol 42 ◽  
pp. 138-141
Author(s):  
G. Zampighi ◽  
M. Kreman
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Transport Proteins ◽  
Molecular Organization ◽  
Passive Transport ◽  
Concentration Gradients ◽  
Cell Functions ◽  
Natural Concentration ◽  
Active Transport System

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.

Pneumatically-driven Microfluidic Device for Evaluating Active Transport by Kinesin Motor Protein

2016 ◽  
Vol 136 (9) ◽  
pp. 384-389
Author(s):  
Kazuya Fujimoto ◽  
Hirofumi Shintaku ◽  
Hidetoshi Kotera ◽  
Ryuji Yokokawa
Keyword(s):  
Active Transport ◽  
Microfluidic Device ◽  
Motor Protein ◽  
Kinesin Motor

A Mechanism for Reversibly Pausing a Self-Immolation Cascade in Response to pH Changes

2019 ◽  
Author(s):  
Derrick Roberts ◽  
Ben S. Pilgrim ◽  
Tristan Dell ◽  
Molly Stevens
Keyword(s):  
Local Environment ◽  
Chemical Signals ◽  
Ph Sensitive ◽  
First Report ◽  
Ph Changes ◽  
Self Immolation

We describe the first report of a self-immolation cascade that can be reversibly paused and reactivated in response to pH changes. This system employs a triazole-based self-immolative linker, which expresses a pH-sensitive intermediate during its elimination sequence. This allows the system to respond to pH cues within its local environment, thus establishing a new way to gate self-immolative release using fluctuating or transient chemical signals.<br>

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